Seal arrangements having two machine parts which are arranged so as to be movable toward one another along a or about a movement axis, wherein one of the two machine parts realizes a seal holding structure and the respectively other machine part realizes a sealing surface, are known from practice. A sealing device which is arranged held on/in the seal holding structure serves for the dynamic sealing of a sealing gap realized between the two machine parts, said sealing device includes a sealing element and a pre-tensioning element which is separate from the sealing element and by means of which the sealing element is tensioned against the sealing surface of the respective other machine part in the radial direction.
Such seal arrangements have long been established, for example, as rotary seal arrangements where, for example, a rotatably mounted rotary shaft is sealed against a housing or a bearing part or also in the case of hydraulic cylinders with a piston which is guided inside the cylinder and is movable translationally.
In the case of commercially available seal arrangements, the sealing element is subject to wear not least because of its friction on the sealing surface of the respective machine part. This affects, in particular, structures of the sealing element which are essential for the sealing performance and also for the fluid return-conveying performance of the seal arrangement. A heavier and correspondingly more robust realization of the sealing part or sealing element in relation to mechanical loads additionally holds the risk of premature wear of structures essential to the functioning. In addition, there is the risk of thermally overloading the sealing element because the frictional heat generated in operation can no longer be adequately removed.
U.S. Pat. No. 2,105,871 A has disclosed a rotary seal arrangement where the sealing device includes a film-like sealing element produced from leather or from another oil-resistant material which bears sealingly against the sealing surface of a rotatably mounted axle. The sealing element, in this case, is pressed against the sealing surface of the axle by means of a simple garter spring. Said design does enable improved heat removal in the region of the sealing element. However, the seal arrangement is little suited to high-pressure applications. Over and above this, the individual windings of the garter spring arranged one behind another in the circumferential direction may only be spaced apart slightly—if at all—in order to ensure a sufficient sealing performance of the sealing device. As a result, a reliable return drag performance for the sealing device is not to be realized.
It is consequently the object of the invention to provide a seal arrangement which is cost-efficient to produce and where the sealing device comprises an improved return drag performance with a simultaneously improved service life.
Said object is achieved by the seal arrangement with the features specified in the independent claim. Preferred further embodiments of the invention are provided in the subclaims and the description.